Teaching Presentation on web Technology.

Chapter-4
Web Technology
Prepared By
Siraj.F.M
HSST Computer Science
AKGS GHSS Peralassery

Web Page

Web pages are developed using HTML(Hyper
Text Markup Language).

It is called language of the internet. Any page
created using HTML are viewed using software
known as Web Browser

Network protocols

It is a set of rules and regulations to transfer data from one
machine to another.

TCP/IP. (Transmission Control Protocol/Internet Protocol) :
It is combination of two protocols TCP and IP.

TCP is responsible for sending data from one PC to
another and checks data packets for errors.

DNS(Domain Name System)

DNS has a database that store domain name and IP
address information of all websites on the internet.

When we type site address, the browser finds the URL and
asks the DNS for URL's equivalent to IP address.

(Numeric address like 216.58.211.14- address of google.com).

The DNS returns the IP address to the browser.

Communication on the Web

In order to communicate on the web, the devices follow the
same protocol, namely TCP/IP. Web sits are accessed
using HTTP (Hyper Text Transfer Protocol ).

The data to be sent is broken down into small data packets
along with the address of the recipient computer by the
TCP protocol.

The routers route and transport these data packets to their
destination computers using internet protocol.

Client to server communication

This type of communication does not require authentication, but
certain application like e-mail, e-banking etc. requires user name and
password due to security reasons.

In such cases HTTPS (Hyper Text Transfer Protocol Secure )
technology is used to encrypt the user name and password.

It works using SSL ( Secure Socket Layer ) which ensures

security . When a request is send by browser the server returns SSL
certificate after verification from the corresponding certification
authority and then starts communication.

This communication takes place in encrypted form. Verisign Inc. is a
certification authority.

Web server to Web server communication

These type of communication takes place in e-commerce
(online shopping ) .

Payment gateway is a server that act as a bridge between
merchant server and bank server and transfers money in
an encrypted form.

Web server

A web server is a computer that process request and distributes
information.

They are often used to host(store) web pages (websites). It
delivers different services such as www, e-mail, blog etc.

Some of the commonly used web server packages are Apache
Server, Microsoft Internet Information Server(IIS), Google Web
Server etc.

Data center

It is used to house computers and associated components.

The main advantage of installing web servers in data
centers are faster internet connectivity and uninterrupted
power supply.

Popular server Operating Systems are Redhat, Debian,
Ubuntu, Microsoft Windows Server, Oracle Solaris etc.

Ports

Hardware ports are used to connect external devices like
keyboard, mouse etc.

Software ports are used to connect a client computer to a
server to access its services like HTTP, FTP, SMTP etc.

Software ports are given a 16 bit unique number.

Ex. A service in a website can be accessed in the following
format. http://google.co.in:80

Here http is the protocol, google.co.in is the domain

name, 80 is the port number.


Some of the commonly used ports and services are

Static and Dynamic web pages

A static web pages contains the same content each time the page is loaded, while the
content of dynamic webpage changes. Web pages created using HTML are usually static.

Dynamic web pages are executed using server side application programs installed on
webserver. Technologies like PHP, ASP, JSP etc are used to create dynamic web pages

Scripts

A script is a program executed on the web page.

The languages that are used to create scripts are called scripting
languages.

They are written using a text editor.

In an HTML page, a script is written inside <SCRIPT> and
</SCRIPT> tags.

Names of popular scripting languages are

Java Script,AJAX,VB Script,PHP

ASP- Active Server Page

JSP - Java Server Page

CSS - Cascading Style Sheet

Types of Scripting Languages

(a) Client side scripting

They are executed on the client browser. They are often used to
validate user input, enhance web pages, performing simple
calculations before sending the data to the web server etc.

Example: Java script, VB Script, DART, Action script etc.

(b) Server side scripting

They runs on a server and are used to create dynamic web pages.
They accepts data, processed data and generates documents. They
can access database.

Some of the popular server side scripting languages are PHP, JSP,
ASP, Perl etc.

Client side scripting Vs Server Side Scripting
Client side scripting Server side scripting
Scripts is copied to the client browser. Scripts remains in the web server.
They are executed by the client browser. They are executed by the web server.
Used for validating user inputs. Used for processing data.
Used to create static web pages. Used to create dynamic web pages.
Some browsers do not support scripts Does not depend on browser.

Scripting Languages

JavaScript

It is a client side scripting language used to create interactive web
pages.

It is mainly used to validate forms.

It works in almost every web browser.

It can also be used for performing simple calculations and also for
bringing animations to a web page.

This code can be inserted inside the HTML code or can be written
as an external file and then included inside the HTML file.

If the code is written as an external file use the file extension ' •js '.


VB Script

VB Script is a scripting language developed by Microsoft Corporation
based on the popular programming language Visual Basic.

It can be used for client side and server side scripting.

PHP (PHP is Hypertext Preprocessor)

PHP is an open source general-purpose scripting language.

It is a server side scripting language and codes are embedded

( or inserted ) inside HTML code.

It is a server side scripting tool and its code is similar to Java,C and Perl.

The PHP file is saved with an extension .php

Advantages of PHP

It runs on different platforms.(Windows or Linux)

Used to develop dynamic web page easily.

It is compatible with different servers.

It supports different databases.

It is an open source language and easy to learn

ASP (Active Server Page )

Microsoft Active Server Pages (ASP) is a server-side scripting
environment that can be used to create and run interactive web
applications.

ASP files have the extension .asp .

These files are compiled using a feature built in Microsoft's web server
software,Internet Information Server (IIS).

It is a very powerful scripting language.

The advantages of ASP

The code written in text mode.

It does not need any server side installation.

ASP applications are very small.

ASP components can be modified without effecting server functions.

JSP (Java Server Pages )

JSP is a server side scripting language developed by Sun

Microsystems.

JSP pages are compiled into servelets before they are
used.

A JSP file has ‘.jsp’ extension.

To run JSP,Apache Tomcat web server is required.

AJAX (Asynchronous Java script and XML )

It is not a programming language, but a way to use
existing standards such as Java script and XML
(Extensible Mark-up Language).

It is a technology used to update parts of web pages
without reloading the whole page.

It is used to create dynamic and interactive web
applications.

Cascading Style Sheet (CSS)

It is a style sheet language used for describing the appearance
of document written in mark-up language such as HTML.

Using CSS,we can control the colour of the text,the style of
fonts,the spacing between paragraphs,how columns are
sized and laid out,borders and its colours,what
background images or colours used, as well as a variety of
other effects in a web page.

CSS allows adapting the presentation of a web page to
devices with different screen sizes such as desktop
monitors,tablets or mobiles.

HTML (Hyper Text Markup Languages )

HTML is used to create web pages.

The commands used in HTML are called tags.

Tags begins with opening angle bracket(<>) and ends with closing angle
bracket(</>).Tags are not case sensitive.

Tags in HTML are of two types.

(a)Container tag

It has a start tag and an end tag.

Eg: and .

Every thing between start and end tags are affected by that container tag.

(b) Empty tag

An empty tag is also known as single tag. It has only opening tag(<>).

Eg: , <hr>, <img>


Attributes

The additional information supplied with HTML tags are
called attributes.

Eg: right aligned paragraph Here '
align ' is the attribute, ' right ' is the value. Here the
paragraph is displayed as right aligned.

Structure of HTML page

An HTML page begins with <HTML> end with </HTML>.

The source code is written using a text editor.

The files are saved with extension .htm or .html.

Teaching Presentation on web Technology.

Example-1
<html>
<head>
<title>charactor entities </title>
</head>
<body bgcolor=#fabf73>

<h1> Following are some charactor
entities</h1>

for double quotation mark "
 
for less than < 
for copyright symbol © 
for Registered Symbol ® 
for Trade mark symbol ™

</body>
</html>

Example-2
<html> <head> <title>SAMPLE PAGE USING DIFFERENT
TAGS</title></head>
<body background="/home/user/Desktop/Slide/plane.jpeg">
 
I am Bold and
Strong 
I am italiced or
Emphasised<hr>
I am underlines
<S>Strike Me</S>
<STRIKE>and Me</STRIKE>
<BIG>" Big Tag is Big "</BIG> 
and Small Tag is Small
A2+B2
H2SO4
<BLOCKQUOTE>A text that can be shown in
bloqckquote</BLOCKQUOTE>
<Q>Quotation text</Q>
<PRE>A text that is given in preformatted form</PRE>
<ADDRESS>Address of the party Contact address 
should be typed here</ADDRESS>
<img src="/home/user/Desktop/Slide/index.jpeg" height="300"
width="300">
</body>
</html>

Thank You
Prepared By
Siraj.F.M
HSST Computer Science
AKGS GHSS Peralassery

Teaching Presentation on web Technology.

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